As an example of a level position measuring means, there has been such type that is a combination of a staff and an optical-type level reads the scale of the staff. This type of means has a disadvantage that the scale of the staff is misread. The measurement with this type of means is completed such that the staff is positioned at a certain distance, and the scale of the staff is read both from the front and the back thereof, then an inking is done manually. The same operation is repeated a number of times. Therefore, other than the measurer who actually reads the scale, an extra person is required, but still the misread of the scale cannot be avoided. Because of such reasons, a means which can automaticaly perform accurate measurement without relying much on human beings is desirable.
For this purpose, in the past, there is apparatus where a laser beam is emitted from a level to a staff, reading the scale of the staff. However, in this prior art, a spot of the laser beam on the staff is rather big, so that it lacks an accuracy of the measurement. Further, another problem of this prior art is that the operator of the level cannot read the scale of the level.
In both optical-type level and laser-type level, there is such disadvantage that an marking has to be done manually relying on human eyes, so that an accuracy of the measurement is unreliable. Further, both means can be applied only on such place that visibility thereof is good. When they are to be applied, for example, on depressed area or a place with obstacles, the levels have to be moved to obtain a good visibility, which became a cause of unacourate measurement.
A level position measuring means in such cases that a room, for example, is so small that a level cannot be used therein and that an accuracy of the measurement is not highly required, a leveling tube, which is a simple tool for measuring a level position, is employed. The leveling tubes are only used by craftsmen and for smaller scale of constructions, but an extent of utilization thereof is still high.
The leveling tube mentioned above is shown in FIG. 5. The leveling tube is arranged such that a rubber hose 3 is connected to the bottom of a water container 2, which is transparent so that the water head 1 can be seen outside thereof, and a glass tube 4 is connected to the edge of the rubber hose 3. The level 6 of the water 5 is stable, so that the water head 7 of the glass tube 4 positions to the level equal to the water head 1 of the water container 2, the reference level.
For smaller constructions, the leveling tube, which does not require an expensive level, is effectively used. However, it has such problems that it takes time until the water level stablizes because of the fluidity of the water in the hose, and that the results of level measuring varies depending on the reader because the water level in the glass tube forms depression because of the surface tension thereof, so that the efficiency and the accuracy of the measurement thereof are unsatisfactory.
The object of the present invention, therefore, is to provide a means for level position measuring comprising a hose, which prevents misreading of measurement.
According to the prior art, marking is done manually relying on human eyes, so that the marking lacks accuracy. Therefore, another object of the present invention is to provide a means for marking which resolves such problem.